The present invention relates to a process cartridge removably installable in the main assembly of an electrophotographic image forming apparatus, and an electrophotographic image forming apparatus.
In this specification, the term xe2x80x9celectrophotographic image forming apparatusxe2x80x9d refers to an image forming apparatus that employs an electrophotographic system to form images on a recording medium. For example, it includes electrophotographic copying machines, electrophotographic printers (laser beam printers, LED printers, and the like), facsimile machines, word processors, and the like.
A process cartridge is a cartridge that integrally comprises a charging means, a developing means or a cleaning means, and an electrophotographic photosensitive drum, and which is rendered removably installable in the main assembly of an electrophotographic image forming apparatus. It also refers to a cartridge comprising at least a charging means, a developing means, or cleaning means, in addition to an electrophotographic photosensitive drum, and is rendered removably installable in the main assembly of an electrophotographic image forming apparatus. It also means a cartridge comprising at least a developing means, and an electrophotographic photosensitive drum, and which is rendered removably installable in the main assembly of an electrophotographic image forming apparatus.
In the past, an image forming apparatus which employed an electrophotographic-image-formation process employed a process cartridge system, according to which an electrophotographic photosensitive member, and one or a plurality of processing means which work on the electrophotographic photosensitive member, are integrally assembled in the form of a cartridge removably installable in the main assembly of an image forming apparatus. Also according to this process cartridge system, the maintenance for an image forming apparatus can be performed by a user him/herself; the user does not need to rely on a service person for the maintenance. Therefore, the employment of a process-cartridge system drastically improved the operational efficiency of an image forming apparatus. As a result, the process-cartridge system has been widely used in the field of the image forming apparatus.
The process cartridge used in the above-described process cartridge system is in the form of a cartridge that comprises: a development unit integrally comprising a development unit frame in which a development roller and a development blade are disposed, and a toner chamber frame that stores toner as developer; and a cleaning unit frame that supports a photosensitive drum, houses a cleaning blade and the like, and is pivotally connected to the development unit.
The present invention is a result of the further development of the aforementioned prior technology.
The primary object of the present invention is to provide a process cartridge capable of more reliably supporting an electrophotographic photosensitive drum, and an electrophotographic image forming apparatus compatible with such a process cartridge.
Another object of the present invention is to provide a process cartridge superior in terms of assembly, and an electrophotographic image forming apparatus compatible with such a process cartridge.
Another object of the present invention is to provide a process cartridge not only capable of reliably supporting an electrophotographic photosensitive drum, but also superior in terms of assembly, and an electrophotographic image forming apparatus compatible with such a process cartridge.
According to an aspect of the present invention, the process cartridge comprises: (a) a development unit that supports an electrophotographic photosensitive drum, and a development member for developing an electrostatic latent image formed on the electrophotographic photosensitive drum, with the use of developer; and (b) a charge unit that supports a charging member for charging the electrophotographic photosensitive drum, and is pivotable about a pivot center in the first direction, that is, a direction to cause the charging member to move toward the electrophotographic photosensitive drum, and also in the second direction, that is, a direction to cause the charging member to move away from the electrophotographic photosensitive drum, and an electrophotographic image forming apparatus in which such a process cartridge is removably installable.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.